Scripting: qet.apiSignatures(), the calls a script can make

Read from the meta-object, so the list is the one the running build has:
for someone writing a script, and for an assistant that has to write one
without the source at hand.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/scripting/qetscriptapi.cpp

@@ -122,6 +122,40 @@ int QetScriptApi::folioCount() const
 	folio, and the first one stands in for it so a script written for the
 	editor can still be tried headless; -1 if the project has none.
 */
+/**
+	@brief QetScriptApi::apiSignatures
+	Every call a script can make, as "returnType name(type param, ...)",
+	read from the meta-object rather than written out by hand, so the list
+	is the one this build has and cannot drift from it: for a person
+	writing a script, and for an assistant that has to write one without
+	the source at hand. A call with default arguments is listed once, with
+	all of them.
+*/
+QStringList QetScriptApi::apiSignatures() const
+{
+	QStringList list;
+	const QMetaObject *meta = metaObject();
+	for (int i = meta->methodOffset(); i < meta->methodCount(); ++i) {
+		const QMetaMethod method = meta->method(i);
+		if (method.methodType() != QMetaMethod::Method
+		    || method.access() != QMetaMethod::Public
+		    || (method.attributes() & QMetaMethod::Cloned)) {
+			continue;
+		}
+		const QList<QByteArray> types = method.parameterTypes();
+		const QList<QByteArray> names = method.parameterNames();
+		QStringList params;
+		for (int p = 0; p < types.size(); ++p) {
+			params << QString::fromLatin1(types.at(p) + ' ' + names.value(p));
+		}
+		list << QStringLiteral("%1 %2(%3)")
+			.arg(QString::fromLatin1(method.typeName()),
+			     QString::fromLatin1(method.name()),
+			     params.join(QStringLiteral(", ")));
+	}
+	return list;
+}
+
 int QetScriptApi::currentFolio() const
 {
 	if (!m_project) return -1;

sources/scripting/qetscriptapi.h

@@ -579,6 +579,9 @@ class QetScriptApi : public QObject
 		// -- logging: a script has no console of its own --
 		Q_INVOKABLE void log(const QString &message);
 
+		// -- what a script can call, read from this class itself --
+		Q_INVOKABLE QStringList apiSignatures() const;
+
 		void setUndoGrouped(bool grouped);
 
 	private:

tests/qttest/tst_scriptcurrentfolio.cpp

@@ -2,6 +2,7 @@
 #include <QtTest>
 
 #include <QFile>
+#include <QJsonArray>
 #include <QJsonDocument>
 #include <QJsonObject>
 #include <QProcess>
@@ -88,6 +89,27 @@ private slots:
 		QCOMPARE(r.value(QStringLiteral("current")).toInt(), -1);
 	}
 
+	// The list is read from the build itself: the calls a script uses
+	// are in it with their parameter names, each once.
+	void apiSignaturesListed()
+	{
+		const QJsonObject r = run(QStringLiteral(
+			"qet.log('PROBE ' + JSON.stringify({sigs: qet.apiSignatures()}));\n"),
+			QStringLiteral(QET_EXAMPLES_DIR "/perceuse.qet"));
+		QVERIFY2(!r.isEmpty(), "the script logged nothing");
+		QStringList sigs;
+		for (const QJsonValue &v : r.value(QStringLiteral("sigs")).toArray())
+			sigs << v.toString();
+		QVERIFY(sigs.size() > 100);
+		QVERIFY(sigs.contains(QStringLiteral("int currentFolio()")));
+		QVERIFY(sigs.contains(QStringLiteral(
+			"int addText(int folioIndex, QString text, double x, double y)")));
+		QVERIFY(sigs.contains(QStringLiteral(
+			"bool exportPdf(QString output, bool showTerminals)")));
+		QCOMPARE(sigs.filter(QStringLiteral(" exportPdf(")).size(), 1);
+		QVERIFY(sigs.filter(QStringLiteral("setUndoGrouped")).isEmpty());
+	}
+
 	void headlessUndoStaysPerCall()
 	{
 		const QJsonObject r = run(QStringLiteral(